1. Field of the Invention
The present invention relates to a rotation detecting device, which is used with vehicle wheels or various machines and equipments for detecting the rotation or the angle of rotation thereof, and a rotation detecting device equipped bearing assembly having the rotation detecting device mounted thereon.
2. Description of Related Art
For accurately detecting a rotating condition of a rotating body of, for example, an automotive vehicle or a railway vehicle, demands have been made to secure a highly accurate rotation signal of a high resolution. In a wheel support bearing assembly for rotatably supporting a vehicle wheel relative to a vehicle body, an ABS sensor is generally employed for controlling an anti-lock brake system, that is, for the ABS control. This ABS sensor available at this time has an insufficient resolving power. If a rotation detection at a high resolving power is possible with such a sensor, it can be used in a sophisticated vehicle control such as, for example, automated driving, automated drive assistance, safety control or the like in the future. As the rotation detecting device, such a circuit system has hitherto been made in which a multiplication signal having a high resolving power is obtained from a rotation signal input of sin and cos detected by a magnetic sensor. In this respect, see the patent document 1 listed below. A schematic construction of this rotation detecting device is shown in FIG. 34 in the form of a block diagram.